In one of known methods of tire manufacture, a base tire, which serves as the base for a tire, and a cured tread, which is to be bonded to the outer periphery of the base tire as the tread of the tire, are molded separately and then the base tire and the tread are integrated with each other into a product tire.
A base tire is obtained, for instance, by removing the tread portion of a used tire with a buffing machine. And the surface after the removal of the tread portion is formed as the bonding surface to which a new tread is bonded. The bonding surface is formed in such away that the cutting part of a grinder is brought into contact with the tread portion of a used tire which is mounted fixedly to the drum of a buffing machine with the internal pressure applied. More specifically, the grinder is moved back and forth repeatedly in the width direction of the used tire while the drum is rotated. Thus the bonding surface is formed into a predetermined shape such that the curvature radius in the axial cross section of the bonding surface is smaller away from the tire axial center toward each side. Bonded to the base tire having the bonding surface of the predetermined shape is a cured tread which has been formed with a fixed thickness or with a thickness thinner away from the axial center toward each side. In this manner, a product tire is completed with these two parts integrated with each other.